Mechanism for moving a load supporting member on a fork lift truck



Oct. 14. 196 w. w. HENDRICKS ET L MECHANISM FOR MOVING A LOAD SUPPORTING Original Filed April 15,

MEMBER ON A FORK LIFT TRUCK 1965 4 Sheets-Sheet 1 0ct.14. 1969 w w nmc s ET AL 3,472,408

a MECHANISM FOR MOVING A LOAD SUPPORTING I MEMBER ON A FORK LIFT TRUCK Original Filed April 13, 1965 4 Sheets-Sheet Hes I I -|NVENTOR3 I W1LLlAM.W. HENDRICKS 4 LAWRENCE M. FREEMAN BY m 'i fwn I ATTO NEYS Oct. 14. 1969 w, w; I'ENDRICKS ET AL 3,472,408

, MECHANISM FOR MOVING A LOAD SUPPORTING MEMBER ON A FORK LIFT TRUCK Original Filed April 13. 1965 4 Sheets-Sheet 3 63 65 I 64 F 19 Hi n EFQ/ [II-H}??? Li, al INVENTORSI BY 12% b.

Oct. 14, 1969 w w, HENDR|K5 ET AL 3,472,408

MECHANISM FOR MOVING A LOAD SUPPORTING MEMBER ON A FORK LIFT TRUCK Original Filed April l3. 1965 4 Sheets-Sheet 4 FIG] FIG. 8

WiLLlAM w. HENDRICKS LAW N B BY mi 945 FEEELMAN ATTORNEYS United States Patent 3,472,408 MECHANISM FOR MOVING A LOAD SUPPORTING MEMBER ON A FORK LIFT TRUCK William W. Hendricks and Lawrence M. Freeman, Atlanta, Ga; Grace H. Hendricks, by court decree, owner of the estate of said William W. Hendricks, deceased; and said Lawrence M. Freeman, assignors to Space Control Corporation, Atlanta, Ga., a corporation of Georgia Continuation of application Ser. No. 447,818, Apr. 13, 1965. This application Aug. 12, 1968, Ser. No. 757,197

Int. Cl. B66f 9/08, 9/20 US. Cl. 214-674 Claims ABSTRACT OF THE DISCLOSURE Side loading apparatus for fork lift industrial trucks wherein the forks can be oriented longitudinally of the truck, or positioned in front of and oriented to the side of the truck, or positioned to one side and oriented to the side of the truck.

This application is a continuation of Ser. No. 447,818 filed Apr. 13, 1965, and now abandoned.

BACKGROUND OF THE INVENTION Industrial trucks having lifting and loading attachments are quite well known and have been used extensively in warehouses and in other areas where various materials must be stacked to be stored and later removed. There have been frequent attempts to provide industrial trucks with loading attachments, or forks, that will rotate 90 degrees with respect to the truck to allow the truck to pick up or deposit material without necessitating the trucks turning in the aisle. This is desirable primarily because, in order to allow a truck to turn within an aisle, the aisles must be substantially wider, thereby reducing the area that can be used for storage.

Past efforts to provide the side loading feature to fork lifts have included various mechanisms for rotating the forks with respect to the mast, and these have entailed very elaborate and complex mechanisms that are expensive to manufacture, and are relatively inefilcient in operation. A severe disadvantage of the prior art methods of providing side loading for the fork lift is the reduction of the weight that the forks can carry when in the side position. Since the conventional fork lift is designed so that the fulcrum point is at the front axle, and the weight of the industrial truck itself provides the resistance to tilting of the truck when carrying a heavy load, the placing of the load to one side of the truck tends to tilt the truck, since the fulcrum is removed from the front axle and is changed to one of the front wheels.

SUMMARY OF THE INVENTION The device of the present invention overcomes the above mentioned and other difliculties by providing, in combination with a conventional industrial truck means for rotating the mast and the forks carried on the mast; and, wheels are placed on the mast so that, when the mast and the forks thereon are in side loading position, the fulcrum point is at the mast. Since, with this construction, the fulcrum point is very close to the load, and rather far removed from the truck, there is almost no tendency for the truck to tilt, even when the mast and the forks thereon are extended beyond the side of the truck.

To give further stability to the truck, outriggers are provided, the Outriggers being foldable so that they can be used or not used. When the outriggers are in position to be used, the load is supported, in effect, on four wheels with the center of gravity of the load substantially centered between the four wheels. Or, only one outrigger may be used, the one outrigger being on the side of the forks that carries the principal load.

Though one form of the device of the present invention includes power means for shifting the mast and the forks from the usual position in which the forks are disposed in front of the truck and with the forks extending forwardly, an alternative provides for a manually operable device. The basic mechanism is so simple, and requires so little force, that the operation thereof can be manual or through some power means.

It will thus be seen that the device of the present invention provides a very simple and efiicient means for shifting the forks of a fork lift into side loading position, and will allow the forks to extend completely beyond the side of the industrial truck. As the forks move, the fulcrum point is also moved so that, regardless of the position of the forks, the forks can carry the maximum load for which the truck is designed.

These and other features and advantages of the present invention will become apparent from consideration of the following specification when taken in conjunction with the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of one preferred embodiment of the present invention, the industrial truck being partially broken away;

FIG. 2 is a view similar to FIG. 1, but showing the forks thereof in position for loading;

FIG. 3 is a front elevational view of the device shown in FIG. 1 with the industrial truck being omitted for clarity, and showing the side loading position of the device in broken lines;

FIG. 4 is a cross-sectional view taken substantially along the lines 44 of FIG. 3, and including a portion of the industrial truck;

FIG. 5 is a top plan view of the mechanism of the present invention with the fork carrying portion thereof in partially rotated position;

FIG. 6 is a view similar to FIG. 5 showing the fork carrying mechanism in fully rotated position in full lines, and showing the mechanism moved to the opposite end in broken lines;

FIG. 7 is a rear elevational view of the mechanism of the present invention, the front axle housing of the industrial truck being shown in broken lines;

FIG. 8 is a cross-sectional View taken substantially along the line 8-8 in FIG. 7;

FIG. 9 is a cross-sectional view taken substantially along the line 9-9 in FIG. 7;

FIG. 10 is a detail of the latch to be used in conjunction with the present invention, the slave block being attached to the stationary latch;

FIG. 11 is a view similar to FIG. 10 showing the latch on the master block disengaging the stationary latch;

FIG. 12 is a view similar to FIG. 11 showing the latch on the master block fully engaged with the slave block, the master block being moved away from the stationary latch; and,

FIG. 13 is a cross-sectional view taken substantially along the lines 13-13 in FIG. 12.

DESCRIPTION OF AN EMBODIMENT Referring more particularly to the drawings, and to FIGS. 1 and 2 thereof, it will be seen that there is a conventional industrial truck 10 having a front axle housing 11 about which the fork mechanism is pivoted, as is conventional. There is a pair of hydraulic cylinders 12, one of which is shown in FIGS. 1 and 2. These also are standard equipment on conventional industrial trucks.

Normally, the mast 19 of a fork lift is attached to a pair of brackets which are pivoted about the front axle housing 11, and to the piston rods 18 of the hydraulic cylinders 12. It will therefore be seen that the mechanism of the present invention is completely adaptable to a conventional industrial truck having a loading mechanism therefor. To convert the conventional fork lift to a side loading fork lift in accordance with the present invention, one need simply to remove the mast 19, and weld, or otherwise affix, the plate 14 to the flanges 15; and, the plate 14 should have ears 16 to which the piston rods 18 will be pivotally attached. The mechanism of the present invention, generally designated at 20, is carried by the plate 14. It will be noticed that the entire assembly of the invention is unitized by a box 17 which carries all parts of the device. The box 17 allows the assembly to be sold as a unit for installation on a conventional fork lift.

The structure of the assembly 20 is shown best in FIGS. 1-7, and includes the plate 14 which is of substantially a T shape, the cross bar of the T, which is designated at 21, being adapted to carry the rest of the mechanism 20. The cross bar 21 extends slightly beyond the sides of the industrial truck 10 and has upper and lower guide bars 22 and 24 attached to the front thereof at the upper and lower edges respectively. A central guide bar 25 is also attached to the front of the cross bar 21, and is disposed between the guide bars 22 and 24. The central guide bar 25 is shaped to provide a dove tail for cooperation with the slave block 26, which will be discussed in more detail hereinafter.

The cross bar 21 is also provided with a rack gear 28, here shown as attached to the upper guide bar 22, the rack gear 28 being adapted tomesh with a pinion gear 29 which is on the shaft 30 of a hydraulic motor 31.

Looking primarily at FIGS. 3 and 7, it will be seen that there is a master block 32 which is mounted for movement along the cross bar 21. The master block 32 is mounted by having a series of rollers attached to the master block and adapted to engage the guide bars 22 and 24 such that the entire weight of the master block is borne by the rollers. In more detail, there are three rollers 34, 35 and 36 attached to the upper portion of the master block 32 and extending rearwardly thereof so that the rollers bear on the top of the guide bar 22. Rollers 38, 39, and are mounted in substantially the same vertical plane as rollers 34, 35, and 36, respectively; but, the axes of the rollers 38, 39 and 40 are rotated 90 degrees with respect to the axes of rollers 34, 35, and 36; therefore, the rollers 38, 39 and 40 are adapted to bear against the rear surface of the guide bar 22.

At the lower edge of the master block 32, there are rollers 41, 42, and 44 which are complements of the rollers 34, 35 and 36; that is to say, the rollers 41, 42, and 44 are directly opposed to the rollers 34, 35 and 36, and bear against the bottom of the guide bar 24. There are rollers 45, 46 and 48 which are complements of the rollers 38, 39 and 49; that is to say, they bear against the front surface of the guide bar 24.

It will thus be seen that, with the twelve rollers described, three rollers bear the greater part of the weight of the master block and the mechanisms carried thereby; the three rollers 38, 39 and 40 bear the rotational forces that are exerted on the upper portion of the master block 32; the rollers 41, 42 and 44 bear a portion of the forces tending to rotate the master block 32 in its own plane; and the rollers 45, 46 and '48 act with the rollers 38, 39 and 40 to bear the rotational forces of the plate 32.

In FIG. 3, it will be seen that the master block 32 has a cut-out portion 49, giving the master block somewhat the shape of a U that is lying on its side. On the upper leg of the U, the hydraulic motor 31 is mounted by a bracket 50; and, there is a cutout 51 in the block 32 so that the pinion gear 29 can extend through the master block 32 and mesh with the rack gear 28. It will thus be seen that, when the hydraulic motor 31 is operated in one direction, the pinion gear 29 will ride along the rack gear 28 to move the master block 32 across the cross bar 21; and, when the hydraulic motor 31 is operated in the opposite direction, the master block 32 will be moved in the opposite direction across the cross bar 21.

As is best shown in FIGS. 3, 4, 5 and 6, there is a pair of arms 52 and 54 that are pivotally attached to the master block 32 by means of pins 55 and 56, the pins 55 and 56 passing through the arms 52 and 54 and into brackets 58 and 59. These arms 52 and 54 extend toward the mast 19 and are attached thereto by welding or the like. There is a strengthening flange 60 and 60 on each of the arms 52 and 54 to aid in supporting the weight of the mast and fork assembly; and, it Will be noticed that the flange 60 on the arm 54 projects out to act as a stop in I'Otating the mast 19.

At this point it should be understood that the mast 19 is completely conventional, and includes a lift cylinder 61 which is adapted to raise and lower the forks 62. The cylinder 61 is usually hydraulically operated, and this arrangement will be conventional; therefore, the exact details are not disclosed herein, since they form no part of the present invention.

Across the back of the mast 19, there is a member 64 having a pivot block 65 to which is pivoted a pair of arms 66 and 66'. Atlhough the provision of the member 64 is a convenient way to provide means for pivoting the arms 66 and 66, it will be understood that many other methods may be used, the important thing being to attach the arms 66 pivotally to the rear of the mast 19.

The opposite ends of the arms 66 and 66' are pivotally attached to the slave block 26, the slave block 26 having a mating shape to co-act with the central guide bar 25, the slave block being adapted to move along the central guide bar 25 from end to end of the cross bar 21. The slave block 26 is also provided with a stop 67 to limit the rotational movement of the arms 66 and 66' about their pivot point on the slave block 26.

The slave block 26 is provided with three dowels, the dowels 69 and 70 being guided, and the dowel 71 being a latch pin. To cooperate with the dowels 69, 70 and 71, there is a latch 72 attached to a forward protruding block 74, the block '74 being stationary with respect to the cross bar 21; and, the latch 72 is pivotal on the block 74. The master block 32 is also provided with a latch 75. It will be seen, especially in FIGS. 10, 11 and 12., that the two latches 72 and 75 are formed with angled outer extremities 76 to act as camming surfaces. The arrangement is such that, when one of the latches is engaged with the latch pin 71, and the opposite latch approaches the latch pin 71, the latch that is already in latching position will be raised as shown in FIG. 11, and the opposite latch will engage the latch pin 71.

At this point, there should be a basic understanding of the operation of the device. With the forks 62 extending straight ahead, aligned with the industrial truck '10, the hydraulic motor 31 can be caused to rotate its shaft 36 and the pinion gear 29. The pinion gear 29 will roll along the rack gear 28 to carry the master block 32 to the left as viewed in FIG. 3. In FIG. 4 it will be seen that the pivot pin 55 is slightly rearward of the pivot pin 63 which attaches the arms 66 and 66' to the pivot block 65; therefore, when the master block 32 attempts to move to the left as viewed in FIGS. 3 and 4, the lever arm provided by the off-set between the pins 55 and 63 will provide an opening force, or rotating force, for the mast 19 and the assembly carried thereon. Thus, with energization of the hydraulic motor 31, the master block 32 will move, causing the mast 19 to move outwardly, pivoting about the pivot pin 55 and guided by the arms 66 and 66'. When the master block 32 moves completely to the opposite end to the cross bar 21, the latch 75 will disengage the latch 72 from the latch pin 71, and will itself become latched with the latch pin 71.

At this point, the mast 19 will have assumed the position shown in FIG. 6 in full lines, the mast being rotated 90 degrees from its original position and disposed at one side of the cross bar 21. Since the slave block 26 has been unlatched from the stationary block 74 and latched to the master block 32, the motor 31 can now be reversed to carry the entire assembly across the cross bar 21 to be disposed in the position shown in broken lines in FIG. 6. It should be observed, and is best shown in FIG. 7, that the master block 32 can extend partially off the cross bar 21, the master block 32 moving off the cross bar 21 sufficiently that one complete set of the rollers is off the guide bars 22 and 24. This still leaves eight of the rollers to carry the load. This feature is desirable in order to have the forks 62 extend well beyond the industrial truck 10 and other parts of the fork mechanism, thus allowing the forks to extend completely under boxes or the like to be picked up.

One important feature of the device of the present invention is the provision of wheels 80 on the mast 19, or effectively on the mast 19. In the normal position of fork lifts, as shown in FIGS. 1 and 2, the fulcrum point is the front axle housing 11 of the industrial truck 10; therefore, when there is a load on the forks 62, the weight of almost the entire truck 10 resists pivoting about the fulcrum point. When the mast 19 with the forks 62 is in the position shown in broken lines in FIG. 6. the weight of a load on the forks 62 will tend to tilt the industrial truck 10 on one side, making the left front wheel of the truck the primary pivot point, and providing a lever arm only as wide as the truck rather than as long as the truck, as is the case with the forks in front position as shown in FIG. 1. The problem is further aggravated by the fact that the wheels that are steered on industrial trucks are generally articulated so that the truck 10 does not have very great stability when forces are applied to attempt to tilt the truck to one side.

The wheels 80 on the mast 10 provide an admirable solution to the above mentioned problems by moving the fulcrum point as the mast is moved, thereby causing a load on the forks 62 to try to lift the entire truck 10, even when the mast is in the position shown in broken lines in FIG. 6.

Referring to FIGS. 1 and 2 of the drawings, it will be seen that, when the mast 19 is disposed vertically, which is the position in which material would be loaded on the fork 62, the wheels 80 are in contact with the floor; however, when the mast 19 is tilted as shown in FIG. 1, which is the transporting position, the wheels 80 are removed from the floor since the pivot point for the entire mast 19 is the axle housing 11.

FIGS. 1-4 show the outriggers 81, one outrigger being on each side of the mast 19 and attached to extension blocks 82 in order to position the outriggers 81 outside the bounds of the mast 19. Outriggers, such as outriggers 81, are well known in fork lift mechanisms; but, outriggers are normally fixed in place so that one truck must be used when the outriggers are desired, and another tnlck must be used when outriggers are not desired. In the present invention, the outriggers 81 are provided with wheels 84 as is common for outriggers; and, the outriggers 81 are pivotable about the pivot point 85 so that the outriggers 81 can be in normal position as shown in FIGS. 1, 3 and 4, or they can be folded into non-use position as is shown in FIG. 2. To retain the outriggers 81 in the desired position, there is a pin 86 which passes through a flange 88 on the outrigger, the pin passing through the flange 88 and into the extension block 82. Two different holes are provided in the flange 88 so that the single pin 86 can be selectively placed through the hole 89, or through the hole 90 to dispose the outriggers 81 in use or non-use position as desired.

It will be further seen that only one outrigger can be used when desired. In certain circumstances, two outriggers may preclude some maneuvers in relatively narrow aisles, especially when handling narrow boxes, pallets or the like; therefore, one can simply omit one of the outriggers, thereby retaining the advantage derived from the stability given by the outrigger, and retaining the advantage of maneuverability within narrow aisles and in handling narrow loads. The one outrigger would be mounted the same as the two shown, to be disposable in use or non-use position.

Optionally, the outriggers can be provided with power means to change the position thereof. The power means here shown (in FIGS. 1 and 2) includes an arm 83 that projects rearward and upward from the end of the outrigger 81; and, a hydraulic cylinder 87 is mounted to move the arm 83, thereby to rotate the outrigger 81 about its pivot point 85. The cylinder 87 can be operated by the lever L.

There may be times that it is not desirable to have the power means for rotating the mast 19 with respect to the truck 10. In these circumstances the device can be built more inexpensively because the mechanism for rotating the mast can be omitted, and simple provision made for rotating the mast manually. To use the device as a manually rotated mechanism rather than a power rotated mcehanism, there is a pin 91 which passes through a hole 92 in the arm 52. There are two holes 94 and 95 in the bracket 58 so that the arm 52 can be pinned in place in one of two positions: closed position as shown in FIG. 4, or open (rotated) position as shown in FIG. 6.

It will be understood that the mast should still be moved transversely of the truck 10 by some power means, since the mast would be very difficult to move when there is a load on the forks 62; however, if the mast is to be rotated manually, all of the rotation mechanism can be omitted, The rotation mechanism, as should be recognized at this point, includes the slave block 26, the arms 66 and 66' which are attached to the slave block, and the latch arrangement for the slave block. It will be seen that omission of these parts will drastically reduce the cost of the apparatus, yet will allow the same versatility of the device, the only difference being that the mast must be rotated manually and pinned into rotated position.

A full set of controls for the motor 31 is not shown; instead, it is contemplated that there would be simply hydraulic lines leading to the motor through a valve to be operated by the control lever L shown in FIGS. 1 and 2. To stop the motor at the end of its travel, there would be mechanical stops to stop the master block 32. Hydraulic systems for fork lifts are conventionally, designed with the parts sufficiently strong that increased pressure will not harm them, and there is a pop-off valve that will bypass the device being operated; thus, when the master block 32 is stopped, the pressure to the motor 31 will build up sufiiciently to release the popoff valve and by-pass the motor 31 to remove the energization from the motor 31.

It will thus be seen that the apparatus of the present invention provides a very simple and relatively inexpensive means for providing a side loading attachment for a fork lift. The movable fulcrum point through the provision of the wheels on the mast 19 allows maximum loading of the forks 62 in any position, regardless of how far to the side the forks are extended, and there is no danger of overturning the industrial truck 10.

The device is extremely easy to operate since the motor 31 must be energized to cause the master block 32 to travel across the cross bar 21 so that the latch 75 will disengage the latch 72 from the latch pin 71 and allow the latch 75 to become engaged with the latch pin 71 so that the slave block 26 is latched to the master block 32. When in this position, the motor 31 will be reversed to carry the entire assembly to the opposite end of the cross bar 21. After the forks 62 have been manipulated to load or unload material as desired, the motor 31 can be again reversed to move the entire assembly to the opposite end of the cross bar 21 and allow the latch 72 to disengage the latch 75 from the latch pin 71 and allow the latch 72 to become engaged with the latch pin 71. After this happens, the master block 32 will be again moved to the opposite end of the cross bar 21 leaving the slave block 26 on the one end to rotate the mast 19 and the assembly connected therewith to place it in the position shown in FIGS. 1-4.

What is claimed is:

1. Apparatus for shifting the forks of a fork lift truck into side loading position, said apparatus including a truck, a mast carried by said truck, forks carried by said mast, an assembly disposed between said mast and said truck, said truck supporting said assembly and said assembly supporting said mast, said assembly including a master block movable transversely with respect to said truck, said mast being pivotally attached to said master block, a slave block movable transversely of said truck, an arm, said arm being pivotally attached both to said mast and to said slave block, means for selectively latching said slave block to said master block, and means for selectively latching said slave block to render it stationary With respect to said truck.

2. Apparatus for moving the forks of a fork lift truck into side loading position, said apparatus having a truck, a mast carried by said truck, and a pair of forks carried by said mast, a cross bar carried by said truck and disposed transversely thereof, a master block movable along said cross bar, a slave block movable along said cross bar, means for selectively latching said slave block to said master block and to said cross bar, one side of said mast being pivotally attached to said master block, an arm, said arm having one end thereof pivotally attached to the back of said mast and the opposite end thereof pivotally attached to said slave block.

3. Apparatus for moving the forks of a fork lift truck into side loading position, said apparatus having a truck, a mast carried by said truck, and a pair of forks carried by said mast, a cross bar carried by said truck and disposed transversely thereof, a master block movable along said cross bar, a slave block movable along said cross bar, means for selectively latching said slave block to said master block and to said cross bar, one side of said mast being pivotally attached to said master block, an arm, said arm having one end thereof pivotally attached to the back of said mast and the opposite end thereof pivotally attached to said slave block, and power means for moving said master block transversely of said cross bar.

4. The apparatus as claimed in claim 3, said power means including a rack gear attached to said cross bar, a pinion gear carried by said master block and meshing with said rack gear, and means for rotating said pinion gear.

5. Apparatus for moving the forks of a fork lift truck into side loading position, said apparatus having a truck, a mast carried by said truck, and a pair of forks carried by said mast, a cross bar carried by said truck and disposed transversely thereof, a master block movable along said cross bar, a slave block movable along said cross bar, latching means for selectively latching said slave block to said master block and to said cross bar, one side of said mast being pivotally attached to said master block, an arm, said arm having one end thereof pivotally attached to the back of said mast and the opposite end thereof pivotally attached to said slave block, said latching means comprising a first latch pivotally mounted on said master block, a second latch pivotally mounted on said cross bar, each of said latches having a camming surface at its outermost end, a latch pin on said slave block, the arrangement being such that, when one of said latches is engaged with said latch pin and the other of said latches approaches said latch pin, said one of said latches will be disengaged from said latch pin by riding up the camming surface of said other latch, and said other latch will become engaged with said latch pin.

References Cited UNITED STATES PATENTS 2,366,378 1/1945 Barrett 214-672 2,753,066 7/1956 Arnot 214-671 2,787,278 4/1957 Mitchell 187-9 X 2,950,831 8/1960 Anzons 214731 3,092,268 6/ 1963 Powers 214-670 3,166,209 1/1965 Haddock 214730 3,216,598 11/1965 McKee et a1. 214-660 2,553,378 5/1951 Miller 21221 3,168,956 2/1965 Jinks et al 214-730 3,225,949 12/ 1965 Erickson et al, 214660 3,272,365 9/1966 Stevens 214-671 3,335,879 8/1967 ,Shaifer 214671 FOREIGN PATENTS 750,793 6/ 1956 Great Britain.

946,691 l/l964 Great Britain. 1,035,569 7/ 1958 Germany. 1,047,719 12/1958 Germany.

828,460 2/ 1960 Great Britain. 1,348,852 12/1963 France.

GERALD M. FORLENZA, Primary Examiner RAYMOND B. JOHNSON, Assistant Examiner US. Cl. X.R. 

